New Zealand Prime Minister Jacinda Arden on Saturday announced that Auckland would begin a seven-day lockdown on Sunday morning, following the discovery of a new case of coronavirus of unknown origin.
With nearly two million residents, Auckland is New Zealand's largest city.
The new infection is being sequenced, health officials said.
The patient developed symptoms on Tuesday and is believed to have been infectious since Sunday, they added. During that time, he visited several public venues.
"Based on this, we are in the unfortunate but necessary position to protect Aucklanders again," Arden said. She added that under the new Level 3 lockdown, people will only be allowed to leave home for essential shopping and work, and that restrictions in the rest of the country would tighten to Level 2, limiting public gatherings.